摘要
针对核电站余热排出系统(RRA)核心设备余排泵的工作环境处于恶劣的气液两相状态,研究含气对其扬程及效率的影响及影响机理。基于SST k-ω湍流模型和欧拉-欧拉非均相模型,对带有分流叶片的余排泵在不同气相体积分数及气泡尺寸下进行数值模拟,分析叶轮中后段速度变化及泵内气相分布情况,探寻气相存在对余排泵性能影响及其机理。结果表明:来流含气会增大水力损失,气相体积分数为5%和10%时,扬程分别下降约9.2%和20.0%,效率分别下降约6.4%和12.5%。余排泵内气相主要分布在叶片压力面侧、分流叶片进口及叶轮导叶间隙处;气相的存在使分流叶片进口段的相对速度在叶片吸力面增幅大于压力面,形成脱流和漩涡,为气相聚集创造条件;叶轮出口绝对速度也发生变化,与不含气的情况相比,气相体积分数为5%和10%时,出口绝对速度平均值分别下降了4.5%和8.9%,且绝对速度在叶片吸力面侧增加,压力面侧下降,加剧了出口流动的不均匀性及导叶内的水力损失。该研究结果可为气液两相工作条件下带分流叶片的余排泵设计提供技术参考,并可推广至其他带分流叶片的离心泵。
Given that the residual heat removal pump(RHRP),a core component of a nuclear power plant’s residual heat removal system(RRA),operates under harsh gas-liquid two-phase conditions,the influence of gas content on its head and efficiency,as well as the underlying mechanisms are investigated.Based on the SST k-ωturbulence model and the Euler-Euler multiphase model,numerical simulations are conducted on an RHRP with splitter blades under varying gas volume fractions and bubble sizes.This study analyzes the velocity variations in the middle and rear sections of the impeller and the gas phase distribution inside the pump,exploring the impact of gas presence on RHRP performance and its mechanisms.The results indicate that gas content in the inflow conditions increases hydraulic losses:at gas volume fractions of 5%and 10%,the head decreases by approximately 9.2%and 20.0%,respectively,while efficiency drops by about 6.4%and 12.5%.Gas primarily accumulates on the pressure side of the blades,at the inlet of the splitter blades,and in the gaps between the impeller and guide vanes.The presence of gas causes a greater increase in relative velocity on the suction side than on the pressure side at the inlet of the splitter blades,leading to flow separation and vortex formation,which promote gas accumulation.Additionally,the absolute velocity at the impeller outlet changes—compared to gas-free conditions,the average absolute velocity decreases by 4.5%and 8.9%at 5%and 10%gas content,respectively.Moreover,the absolute velocity increases on the suction side and decreases on the pressure side,exacerbating flow non-uniformity at the outlet and hydraulic losses in the guide vanes.These findings provide technical guidance for the design of RHRPs with splitter blades under gas-liquid two-phase conditions and can be extended to other centrifugal pumps with splitter blades.
作者
高俊浩
杨垚
刘雷
周宸宇
刘立军
GAO Junhao;YANG Yao;LIU Lei;ZHOU Chenyu;LIU Lijun(School of Energy and Power Engineering,Xi’an Jiaotong University,Xi’an 710049,China)
出处
《西安交通大学学报》
北大核心
2025年第7期129-139,共11页
Journal of Xi'an Jiaotong University
基金
陕西省重点研发计划资助项目(2024PT-ZCK-68)。
关键词
余排泵
气液两相
分流叶片
扬程
效率
residual heat removal pump
gas liquid two-phase system
splitter blades
head and efficiency
作者简介
高俊浩(2002-),男,硕士生;通信作者:刘立军,男,教授,博士生导师。
